Aromatic polyesters (polyarylates) are a class of polyesters generally made from a bisphenol and an aromatic diacid. Heretofore, the prior art has taught that polyarylates preferably are made in a two-step process starting with the bisphenol and reacting with such as acetic acid or acetic anhydride to prepare a diacetate of the bisphenol, followed by reaction with an aromatic diacid. In general, the prior art has taught that satisfactory polymer cannot be made from such as Bisphenol-A diacetate and aromatic diacids in the absence of a solvent, which, of course, adds another reactant to control, later separate, and in a commercial process recover for recycle.
In addition to the cumbersome nature of a multi-step process, the polyarylates in the past have frequently been unduly brittle, or had low inherent viscosities, or have been dark colored which is undesirable, or some combinations of these undesirable features.
Needed is a simple, effective, useful process to produce polyarylates conveniently, with a minimum of reagents, and yet result in a product of good moldability, suitably high inherent viscosity, and low color.